Divers recovered a body Tuesday morning from a suburban Detroit lake believed to be that of a missing Michigan woman who authorities say was murdered by her plumber for diamond jewelry.

Macomb County Sheriff Mark Hackel said he believed the corpse is Marilou Johnson, a 50-year-old mother of three missing since June 14. The body was found wrapped in a blanket and weighted down with cinder blocks 30 feet below the surface of Cass Lake in Oakland County's West Bloomfield Township.

Click here for MyFoxDetroit.

"They brought it to shore ... we looked at the facial features [and] it looks to be Marilou Johnson," Hackel said.

Johnson last was seen by her live-in boyfriend on June 14 at their home in Macomb County's Washington Township, about 30 miles north of Detroit. She was reported missing the next day.

The sheriff held off on officially saying it was Johnson, because he wanted the county medical examiner and family members to identify the remains.

Earlier Tuesday, Hackel expressed confidence they'd find the body. "With all the evidence and information we have right now, we're confident that she actually is in the lake," he said.

On Monday, officials found Johnson's purse in the lake with her driver's license, credit cards, passport, checkbook and cell phone in 70 feet of water. Inside also was a necklace that belonged to Johnson. Diamonds had been removed from the necklace.

Police found a pill bottle containing five diamonds when they arrested Wright Saturday following a traffic stop in Roseville. The diamonds matched those in a photograph of Johnson's necklace.

Authorities put Wright under surveillance after they learned he had gone to her home on June 14.

On Monday, authorities charged David J. Wright with murder, kidnapping and larceny Monday in connection with Johnson's death.

Asked if investigators had determined a motive, the sheriff said, "It was money."

Click here for FOXNews.com's Crime center.

"We know he knew the family and probably knew about their financial situation and took advantage of them in a desperate time," Hackel told WWJ-AM on Monday. "Marilou is dead as a result of this guy wanting some money."

Wright told investigators Johnson was stabbed in the throat with a fishing knife after he lured her into his trailer outside her secluded home, according to court information filed Monday.

The information said Johnson was stabbed after Wright tripped over a step and fell.

Hackel said Wright had gone to Johnson's home to give an estimate for plumbing work.

Wright told investigators he planned to demand money from her boyfriend, who was inside the house, according to the court records which also stated that he went in and stole Johnson's purse after she was stabbed.

Johnson, 50, last was seen June 14 at her Washington Township home about 30 miles north of Detroit, where she lived with her boyfriend, Roger Blanchard, and her three sons from a previous relationship. Blanchard reported her missing the following night.

Blanchard, Johnson's sons and Wright's family cooperated with investigators, Hackel said.

The Associated Press contributed to this report.

Click here for FOXNews.com's Crime center.